Generally, parts in an engine compartment of a vehicle need excellent rigidity in order to support the vehicle and excellent heat resistance in order to endure the high temperature of the engine, therefore engineering plastics, such as nylon, have been used in the related art.
For example, the most commonly used plastic used as a suction manifold in the engine compartment of the vehicle is a nylon resin composition. Nylon resin has relatively excellent rigidity, and the rigidity may be further supplemented by adding an inorganic material. Resin compositions having various rigidities can be manufactured by combining glass fibers (GF) and using the polarity of the nylon resin itself.
However, even though the nylon resin has excellent physical properties, since specific gravity and prime cost of the material are higher than those of a general plastic material, such as a polypropylene resin, parts made of the nylon resin are heavy and increase production cost.
Therefore, in accordance with a demand for developing a polypropylene resin composition which facilitates a reduction in weight and cost, and has excellent rigidity and heat resistance, a development method of a material in which an inorganic filler or the other resin is combined with the polypropylene resin has been proposed.
Korean Patent Application Laid-Open No. 2003-56188 discloses a method of manufacturing a polypropylene resin composition which includes 36.0 to 78.0 wt % of polypropylene, 10.0 to 30.0 wt % of nylon, 10.0 to 30.0 wt % of a glass fiber, 1.0 to 4.0 wt % of denatured polypropylene as a compatibilizer, and 0.01 to 2.0 wt % of an organic silane-based compound to improve strength and heat resistance. However, the rigidity and impact strength are not sufficiently high enough in the aforementioned technology.